Custer Decking in Marietta Has to Answer to the Weather
Marietta sits close enough to Puget Sound and Drayton Harbor that salt air is part of daily life, and Whatcom County adds its own long, wet winters on top of that. A deck out here isn't just outdoor furniture placement — it's a structure that spends most of the year damp, gets a fine coating of salt-laden moisture off the water, and sits in shade long enough each winter to grow moss on anything that holds water. Composite decking has become the go-to choice for homeowners in this part of the county specifically because it handles that combination better than most alternatives, but only when it's specified and installed correctly for these conditions.
This page is about composite decking as a service for Marietta homes specifically — what the local climate demands from the material, what a correct installation looks like, and how we approach the job when we know the site is going to face salt, rain, and moss for the life of the deck.
What Salt Air, Driving Rain, and Moss Actually Do to a Deck
Salt Air
Airborne salt doesn't just affect boats and metal railings — it accelerates corrosion on any exposed fasteners, hinges, and hardware, and it can gradually degrade lower-grade finishes on wood and some composite products. Over years, homes closer to the water see faster wear on anything with unprotected metal or a weak surface coating than homes further inland in the county.
Driving Rain
Rain that comes in sideways off the water doesn't just fall on the deck surface — it drives into board gaps, ledger connections, and any point where the deck meets the house. If water isn't given a way to drain and dry out, it sits in end grain, fastener holes, and joist tops, which is where rot and mold problems start regardless of what the surface boards are made of.
Moss Season
Whatcom County's overcast, wet stretch from fall through spring is long enough that any shaded or north-facing deck surface will grow moss if it stays damp. Moss holds moisture against the board surface, and on the wrong material that moisture works its way into the wood fibers underneath a thin cap or coating. On a deck that doesn't get much direct sun — common under mature trees or on the shaded side of a house — moss isn't a maybe, it's a certainty without some planning.
Why Composite Decking Fits This Climate
Composite decking is a manufactured board, usually a blend of wood fiber and plastic, often with a plastic "cap" layer bonded around the outside. Compared to solid wood, it doesn't need annual staining or sealing, doesn't splinter as it ages, and resists rot in the board itself far better because the wood fiber inside is encased rather than exposed. That matters directly for Marietta:
- Capped composite sheds surface moisture instead of absorbing it, so driving rain doesn't soak into the board the way it does with uncapped wood.
- A dense composite surface gives moss and mildew less to grip onto, and what does grow washes or scrubs off more easily than it does out of open wood grain.
- Composite doesn't need annual refinishing, which matters on a coastal property where staining or sealing wood every year is a real maintenance burden.
- Quality composite holds its color and structure better under salt exposure than uncoated wood, which grays and roughens faster near the water.
None of that means composite is maintenance-free — we'll get to what it still needs — but it starts from a much better position for this specific climate than raw lumber does.
Where Composite Decks Actually Fail (and How We Avoid It)
Most composite deck problems we get called out to fix aren't about the boards themselves — they're about what's underneath or around them. This is the part of the job that separates a deck that looks fine for two years from one that holds up for two decades in a place like Marietta.
The Substructure
Composite boards are only as good as the frame they sit on. Untreated or under-protected joists beneath a composite deck can rot out of sight while the surface still looks perfect, because the boards themselves hide the problem. We use joist tape or an equivalent moisture barrier on top of every joist to keep water from pooling where the board meets the frame — a step that's easy to skip and one of the most common causes of hidden rot we find on decks near the water.
Drainage and Airflow
A deck that can't breathe underneath stays damp longer after every rain, which extends moss season on the surface and invites rot below it. Proper joist spacing, ledger flashing, and keeping the deck's underside clear of debris all matter more here than they would in a drier climate.
Fasteners and Hardware
Given the salt exposure, we use stainless steel or coated fasteners and hardware rated for coastal exposure rather than standard galvanized hardware, which corrodes faster near saltwater. Hidden fastener systems also reduce the number of exposed metal points on the board face, which helps both appearance and long-term corrosion resistance.
Ledger Board Connection
Where the deck attaches to the house is the single most common source of water intrusion into the structure itself. Correct flashing at this connection is non-negotiable in a climate with this much driving rain — it's the difference between water running off the deck and water working its way into the house framing.
Composite vs. Other Decking Materials for a Marietta Property
| Material | How it handles salt air & rain | Moss/mildew resistance | Ongoing maintenance |
|---|---|---|---|
| Capped composite | Strong — plastic cap sheds moisture and resists salt-driven surface wear | Good — dense surface, moss washes off more easily | Periodic cleaning; no staining or sealing |
| Uncapped/basic composite | Moderate — more absorbent than capped boards over time | Fair — can hold moisture at the surface | Occasional cleaning; some products need more upkeep than premium capped lines |
| Pressure-treated wood | Weaker — absorbs moisture, salt accelerates graying and checking | Poor — open grain holds moss and mildew | Annual staining/sealing to keep rot at bay |
| PVC decking | Strong — fully synthetic, doesn't absorb water | Good — smooth surface | Low; can run hotter underfoot in direct sun |
We install composite most often in Marietta because it strikes the best balance of upfront cost, low ongoing maintenance, and real durability against this specific climate. PVC is a reasonable alternative for homeowners who want the lowest possible maintenance and are less concerned about surface heat in full sun; we'll talk through that trade-off honestly during an estimate rather than push one product over another.
How We Approach a Composite Decking Project Here
1. On-Site Assessment
We look at sun exposure, drainage patterns, proximity to the water, and the condition of any existing structure before recommending a board line or fastening system. A deck tucked under trees on the shaded side of a Marietta lot gets treated differently than one in full, open exposure closer to the water.
2. Frame and Substructure Work
If we're replacing an old deck, we inspect the ledger board, joists, and posts for rot or corrosion before anything new goes down. Reusing a compromised frame under new composite boards just hides a problem instead of fixing it — we won't do that.
3. Moisture Management Details
Joist tape, correct flashing at the house connection, and attention to drainage slope are built into every job, not offered as an upsell. These are the details that determine whether the deck is still solid in fifteen years.
4. Installation
Board spacing, fastening method, and picture-framing (trim boards around the perimeter) are set to manufacturer spec and adjusted slightly for our climate — a little extra attention to gapping, for instance, accounts for how much this deck will see rain and humidity swings across the year.
5. Walkthrough
We go over what the new deck needs from the homeowner going forward — realistically not much, but a few honest points below — before we consider the job finished.
Living With a Composite Deck Through Whatcom County's Moss Season
Composite decking cuts maintenance dramatically compared to wood, but "low-maintenance" isn't "no-maintenance," especially with a wet season as long as ours. A simple seasonal routine keeps a Marietta composite deck looking right year-round:
- Sweep leaves and debris off the surface regularly in fall — trapped organic matter is what feeds moss and mildew growth.
- Rinse the deck with a garden hose periodically through the wet months to keep salt residue and grime from building up.
- Use a soft-bristle brush and a mild soap-and-water solution (or a composite-safe cleaner) on any moss or algae spots rather than a pressure washer set too aggressively, which can damage the cap surface.
- Check that gaps between boards stay clear so water keeps draining through rather than pooling.
- Inspect fasteners and hardware once a year for any early signs of corrosion, particularly on decks closer to the water.
What Drives Cost on a Marietta Composite Deck
| Factor | Why it matters here |
|---|---|
| Board tier (capped vs. basic composite) | Higher-tier capped boards cost more up front but hold up better against salt exposure and moss over time |
| Substructure condition | Rotted or corroded framing found during tear-off adds cost but shouldn't be skipped in a climate this wet |
| Fastener and hardware grade | Coastal-rated stainless hardware costs more than standard galvanized but is worth it this close to the water |
| Sun exposure and drainage layout | Shaded, poorly drained sites may need extra structural detailing to manage moss and moisture long-term |
| Size and design complexity | Multi-level decks, built-in seating, or custom railing add labor beyond a straightforward rectangular deck |
We don't quote from a distance for this reason — the right specification for a shaded, moss-prone lot near Drayton Harbor can look different from one for a sunnier lot further inland, even within the same general Custer service area.
Why a Crew That Already Works Marietta Makes a Difference
A lot of what protects a composite deck here isn't printed on the product warranty — it's judgment calls about flashing details, fastener selection, and framing protection that come from having actually built and repaired decks in this specific microclimate. A crew that mostly works drier, inland areas may not default to coastal-rated hardware or extra moisture barriers unless asked, because they haven't had to deal with the failures that show up when those steps get skipped near the water. Working regularly in and around Marietta and the rest of the Custer area means we've seen how decks age here specifically, not just in general, and we build accordingly from the start rather than learning it through a callback.
If you're weighing composite decking for a home in Marietta or elsewhere around Custer, we're happy to walk the site, look at your sun and drainage situation, and put together a straightforward, no-pressure estimate — just fill out the form below to get started.